This may be a minor/petty issue, so apologies in advance.
I historically tithe (10%) to my church. It's a not insignificant portion from my POV. I've been reading, praying, talking etc. about Orthodoxy and starting to hesitate on whether I should continue to contribute to the church I attend, or put a portion aside (in a separate, non-touchable account) in case I convert, in which case the rolled funds would go to wherever I converted into... if that makes sense. I've kind of split the difference so far by lowering what I give and putting a chunk into a build-up account until I know what I should do with it. I'm even seriously considering creating a donor-advised fund so that the funds are formally designated for giving, but don't have to be given away until know where they should go.
Naturally, I have lots of other questions around reception of the sacraments, but since I'm numbers-oriented, this question bothers me more than most.

Is it better to give, even if I'm giving to the "wrong" church, since I'm not sure? Is it possible that such donations would be harming my ability to discern the truth? Thoughts?
Also, I have historically given above the tithe to a poverty program run by Catholics. It is very, very well run but I'm wondering if this is also problematic. If so, should I give to secular sources? Look specifically for Orthodox ones?